Double insulated drill bit sharpener

ABSTRACT

A double insulated drill bit sharpener including an electric motor supported within a casing and including an output rotary shaft. A sharpening head is fixed to the casing and includes a sharpening wheel fixed to a rotatable spindle coupled to the motor driven shaft.

Oct. 3, 1972 United States Patent Stielper "RRRTRRRR .5 N444044HU33373311 HHHHHHHJ 35 55 In m m wk cm u "83 1 m m mfim "m m d e 0 t LE-lO n i h UMME f RM HSP MGW B 1 7 wwwwwxw 999999999 HHHHHHHHH 2398882 935070590 09259538 3J9fi 3040 484 2577492 4 2 2222223 n. u mm T m I m H mL .U r. m M D 0 D mm 7 m k 0 w A CT 9 J h 0 u n m a n L 6 S n um mum N H.I 7 E m L r e W" w W N A m i d w OH m s "m P DS I A F A l 1 1 1 M 2 3 2I. 5 l U U U n d E u m .m a m ..m d m .m lo r S m Y m. "h e p rm a n G m.u m y b m H mm mm d Tm m m y .m mi mu .m E M h U D m rd 1 mm m m d 6 8UQWWH QhmR 51 1 mJ i 1R m9B U5 mu 54 n B 2 4% R/ no 1 F 1 MR0 W mm m m Mm mm m mhl m m U 1 d 5 M U Mr. H UN 5 55 electric motor supported withina casing and including [56] References Cited an output rotary shaft. Asharpening head is fixed to UNITED STATES PATENTS the casing andincludes a sharpening wheel fixed to a n w d r. f u m .w 0 F m m e m m mm M mm c m w c d 0 n l D.

RR 55 44 33 NH f n mm &m n MD '8 5S 99 NH 006 Willi PATENTEDunr 3 m2SHEET 1 [IF 2 INVENTOR.

PATENTEDB SHEET 2 OF 2 FIG. 5

INVENTOR- R/ E D- L F TM Q Y\ R N m DOUBLE INSULATED DRILL BITSI-IARPENER SUMMARY OF THE INVENTION The present invention is directedto an electric powered, drill bit sharpener which includes a casinghaving an electric motor disposed therein. A sharpening head including arotatable wheel is supported upon the casing. The wheel is driven by themotor through a unique coupling which accommodates small tolerances andmisalignment between parts. Also, the coupling and casing areconstructed to double insulate the unit for operator safety.

Main objects of the present invention are to provide an electricpowered, drill bit sharpener which is double insulated and whichutilizes a unique coupling between a sharpening wheel spindle and adriving motor output shaft, which coupling electrically insulates theformer from the latter and, in addition, accommodates small tolerancesand misalignment therebetween.

Further important objects of the present invention are to provide anovel drill sharpener of the above character which is compact, lightweight, safe and efficient.

Additional important objects are to provide a drill sharpener of theabove character which is relatively inexpensive to manufacture, ruggedin construction, and reliable in use.

Other objects and advantages of this invention will become more apparentfrom a consideration of the detailed description to follow taken inconjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional viewillustrating a drill sharpener embodying the present invention;

FIG. 2 is a sectional view of the structure of FIG. 1 taken along theline 2-2 thereof;

FIG. 3 is a top plan view of the structure of FIGS. 1 and 2 to a largerscale;

FIG. 4 is an exploded perspective view of the lower portion of thesharpener casing construction;

FIG. 5 is a sectional view of the structure of FIG. 3 taken along theline 5-5 thereof;

FIG. 6 is a perspective view of the coupling utilized in the presentinvention.

BROAD STATEMENT OF THE INVENTION Broadly described, the presentinvention relates to a drill sharpener including a casing, an electricmotor supported within said casing and having an output rotary shaft, asharpener head fixed to said casing, said head having a spindlerotatably supported thereon, an abrasive sharpening wheel fixed to saidspindle, a torque transmitting coupling having at least one end thereofformed of hollow, cup-shaped configuration loosely and non-rotatablyreceiving one end of said spindle, said coupling having its other endthreaded into said shaft, whereby to electrically insulate said shaftfrom said spindle and accommodate small tolerance variations andmisalignment therebetween.

In still another aspect, the present invention relates to a drill bitsharpener comprising a motor housing having an electric motor therein,an electrically insulating casing including first and second telescopedmembers enclosing said motor housing, a baffle fixed within one of saidcasing members and supporting said motor, said baffle being constructedof electrically. insulating material and cooperating with said onecasing member, whereby to retain electric conductor means in placewithin said one casing member, a sharpener head including a body fixedto said casing and having a spindle rotatably supported thereon, anabrasive wheel fixed to said spindle, said motor having a rotatableoutput shaft, and insulating means coupling said motor shaft to saidspindle.

In yet another aspect, the present invention relates to a drillsharpener comprising an electrically insulating casing, an electricmotor supported within said casing and having an output shaft, asharpener head fixedly supported upon said casing, an abrasive wheelencased within and rotatably supported upon said head and coupled tosaid shaft, said abrasive wheel having a conical end face defining asharpening surface, said head having means thereon to guide and supportselected sized drill bits with their cutting lips in stationarysharpening engagement with said sharpening surface.

In still another aspect, the present invention relates to a drillsharpener comprising an electric motor enclosed in a housing, said motorhaving transmission means within said housing and an output shaftaccessible from outside said housing, an electrically insulating casingsubstantially completely enclosing and trapping said housing therein, asharpener head fixedly supported upon said casing, an abrasive wheelrotatably supported within and upon said head and having a conical endface defining a sharpening surface, and rotatable about an axissubstantially aligned with the axis of said output shaft, means couplingsaid output shaft and abrasive wheel for conjoint rotation, said headincluding means locating drill bits with their cutting lips instationary sharpening engagement with said sharpening surface, electricswitch means for said motor, said switch means being disposed withinsaid casing and including an electrically insulating operator accessiblefrom outside said casing.

DETAILED DESCRIPTION Referring now more specifically to the drawings, adrill sharpener embodying the present invention is illustrated generallyat 11 in FIG. 1 and is seen to include a motor housing 13 enclosing anelectric motor 14. The motor housing 13 is disposed within a pair oftelescoped insulating members 15, 16 which together form an insulatingcasing for the motor housing 13. The motor housing 13 is seated withinan insulating baffle 17 fixed to the casing member 16 by screws 18, andhas an end bell 26 which bottoms against ribs 19 formed on the casingmember 16. The casing member 15 is secured to the casing member 16 bylong screws 21 and has bosses 23 which bear axially against the upperend of the motor housing 13. Heads 25 of motor housing screws arereceived in openings 27 in bosses 23 for location and stability of theparts. In addition, a resilient member 28 between the bottom of casing16 and the end bell 26 to hold the upper part of the motor housing 13against the bosses 23.

The motor 14 includes a rotatable armature 29 which drives an outputshaft 31 through a transmission located within a gear case 33. Electricpower for the motor 14 is supplied from a source through a line cord 35which extends into the casing member 16 and is supported by a strainrelief 34. The line cord 35 includes a pair of conductors 36, 38 whichare connected to a slider switch 37 and the motor 14. Another conductor32 connects the slider switch 37 to the motor 14. Another slider 39,constructed of an electrically insulating material, is interconnectedwith the slider 37 and has a finger portion 40 disposed exteriorly ofthe casing member 16 for operator control of the motor 14.

Casing member 15 does not enclose any live electric parts and may bemade from relatively inexpensive electrically insulating material suchas for example, Acrylonitrile-Butadiene-Styrene (ABS). CYCOLACmanufactured by Marbon Chemical, Division of Borg- Warner Corp., is asuitable material. The casing member 16 and the baffle 17 enclose liveelectric parts and for double insulation purposes, are formed from anelectrically insulating, self-extinguishing, relatively high temperatureresistant material such as, for example, a phenylene oxide. NORYU,manufactured by General Electric Co., is one example. Thus, theconductors 32, 36 are disposed in a way defined by a dependent skirt 46and a plurality of lugs 50 along one side of the baffle 17, and aplurality of upstanding lugs 48 on the casing member 16, (see FIG. 4).The conductor 38 is disposed in a way defined by a dependent skirt 44and a lug 52 along the other side of the baffle 17, and an upstandinglug 54 on the casing 16. This construction insures that the conductors32, 36, 38 cannot reach any of several air inlet slots 56 in the casingmember 16 should these conductors break anywhere along their length. Thespaced arrangement of the lugs 48, 50 and the relatively small lugs 52,54 allows adequate cooling air to flow around skirts 46, 44 andcirculate into motor housing 13.

A drill bit sharpener head 42 includes a cast metal body 41 removablysecured to the insulating casing member 15 by screws 43. A spindle 45 isrotatably supported within the body 41 by bushing 47 and has an abrasivegrinding wheel 49 secured thereto by a nut 51. The body 41 has aplurality of generally parallel openings 53 of different sizes formedtherethrough which align with a conical sharpening surface 55 of thewheel 45. in use, a drill bit to be sharpened is inserted through asuitably sized opening 53 and pressed against the surface 55 of rotatingwheel 45.

The drill bits are angularly located for proper sharpening in theopenings 53 by means of a plate 57 which has apertures generally alignedwith openings 53 and shaped to engage at least one of the flutes in thedrill bits. This plate 57 may be angularly adjustable about the spindle45 by means of an eccentric knob 59 rotatably supported upon the body41. However, this construction forms no part of the invention and is notdescribed further here. For a detailed explanation thereof, referencemay be made, however, to the copending application of S. G. Enders, Ser.No. 17,109, filed March 6, I970, and owned by the assignee of thepresent application.

According to an important feature of this invention the motor drivenshaft 31 is interconnected with the spindle 45 by a novel coupling 61which serves to electrically insulate the latter from the former andcompensates for small tolerance variations and misalignmentthercbctwecn. This coupling 61 is constructed from a relatively strong,rigid non-conductive material. Glass reinforced ZYTEL", manufactured byE. l. Dupont de Nemours and Co., Inc., is satisfactory. This coupling 61includes a first, generally cylindrical portion 63 threaded into shaft31, and a second cup shaped portion 65 fitted over nut 51. The internalconfiguration of cup-shaped portion 65 is generally complimentary to butslightly larger than nut 51. Thus, rotation is transmitted from shaft 31to nut 51 and spindle 45 through the coupling 61. By means of theslightly larger size of the portion 65 relative to the nut 51, smalltolerance variations between and misalignment of the shaft 31 andspindle 45 is accommodated. However, the lower end of the spindle 45 ishollow and fits over a cylindrical projection 66 formed integral with hecoupling 61 to help align the spindle 45 and the shaft 31.

Further, the non-conductive nature of the coupling 61 electricallyinsulates the spindle 45 from shaft 31. This together with thenon-conductive nature of the casing members 15, 16, baffle 17, andslider 39 renders the entire sharpener l 1 double insulated and safe tothe operator even if the functional insulation in the motor 14 andhousing 13 breaks down.

By the foregoing, there has been disclosed a novel double insulateddrill bit sharpener and coupling calculated to fulfill the inventiveobjects set forth, and while a preferred form of the invention has beenillustrated and described in detail, various additions, substitutions,modifications and omissions may be made thereto without departing fromthe spirit of the invention.

lclaim:

l. A drill sharpener including a casing, an electric motor supportedwithin said casing and having an output rotary shaft, a sharpener headfixed to said casing, said head having a spindle rotatably supportedthereon, an abrasive sharpening wheel fixed to said spindle, a torquetransmitting coupling having one end thereof formed of hollow,cup-shaped configuration and loosely and non-rotatably receiving one endof said spindle, said coupling having its other end threaded into saidshaft, whereby to electrically insulate said shaft from said spindle andaccommodate small tolerance variations and misalignment therebetween.

2. A drill bit sharpener comprising a motor housing having an electricmotor therein, an electrically insulating casing including first andsecond telescoped members enclosing said motor housing, a baffle fixedwithin one of said casing members and supporting said motor, said bafflebeing constructed of electrically insulating material and cooperatingwith said one casing member whereby to retain electric conductor meansin place within said one casing member, a sharpener head including abody fixed to said casing and having a spindle rotatably supportedthereon, an abrasive wheel fixed to said spindle, said motor having arotatable output shaft, and insulating means coupling said motor shaftto said spindle.

3. A drill sharpener comprising an electrically insulating casing, anelectric motor supported within said casing and having an output shaft,a sharpener head fixedly supported upon said casing, an abrasive wheelencased within and rotatably supported upon said head and coupled tosaid shaft, said abrasive wheel having a conical end face defining asharpening surface, said head having means thereon to guide and supportselected sized drill bits with their cutting lips in stationarysharpening engagement with said sharpening surface.

4. A drill bit sharpener ad defined in claim 3 which includes meanselectrically insulating said motor from said sharpening head.

5. A drill sharpener as defined in claim 4 wherein said insulating meansincludes an insulating coupling interconnecting said shaft and a spindleto which said abrasive wheel is fixed.

6. A drill sharpener as defined in claim 3 wherein said casing includesa pair of telescopic members axially trapping said motor therebetween.

7. A drill sharpener as defined in claim 6 which includes a baffle fixedto one of said members and laterally supporting said motor.

8. A drill sharpener as defined in claim 3, wherein said casing includesseparable, electrically insulating members enclosing said motor, a linecord extending from said casing for connecting said motor to an electricsource, electrical switch means on said casing, electrical conductorswithin said casing and connecting said motor, said switch, and said linecord, said casing members defining a wireway confining said conductors.

9. A drill sharpener comprising an electric motor enclosed in a housing,said motor having transmission means within said housing and an outputshaft accessible from outside said housing, an electrically insulatingcasing substantially completely enclosing and trapping said housingtherein, a sharpener head fixedly supported upon said casing, anabrasive wheel rotatably supported within and upon said head and havinga conical end face defining a sharpening rotatable about an axissubstantially aligned with the axis of said output shaft, means couplingsaid output shaft and said abrasive wheel for conjoint rotation, saidhead including means locating drill bits with their cutting lips instationary sharpening engagement with said sharpening surface, electricswitch means for said motor, said switch means being disposed withinsaid casing and including an electrically insulating operator accessiblefrom outside said casing.

10. A drill sharpener as defined in claim 1 wherein said coupling has acylindrical projection in said cupshaped end adapted to fit into saidone end of said spindle, whereby to help align said spindle and saidshaft.

1. A drill sharpener including a casing, an electric motor supportedwithin said casing and having an output rotary shaft, a sharpener headfixed to said casing, said head having a spindle rotatably supportedthereon, an abrasive sharpening wheel fixed to said spindle, a torquetransmitting coupling having one end thereof formed of hollow,cup-shaped configuration and loosely and non-rotatably receiving one endof said spindle, said coupling having its other end threaded into saidshaft, whereby to electrically insulate said shaft from said spindle andaccommodate small tolerance variations and misalignment therebetween. 2.A drill bit sharpener comprising a motor housing having an electricmotor therein, an electrically insulating casing including first andsecond telescoped members enclosing said motor housing, a baffle fixedwithin one of said casing members and supporting said motor, said bafflebeing constructed of electrically insulating material and cooperatingwith said one casing member whereby to retain electric conductor meansin place within said one casing member, a sharpener head including abody fixed to said casing and having a spindle rotatably supportedthereon, an abrasive wheel fixed to said spindle, said motor having arotatable output shaft, and insulating means coupling said motor shaftto said spindle.
 3. A drill sharpener comprising an electricallyinsulating casing, an electric motor supported within said casing andhaving an output shaft, a sharpener head fixedly supported upon saidcasing, an abrasive wheel encased within and rotatably supported uponsaid head and coupled to said shaft, said abrasive wheel having aconical end face defining a sharpening surface, said head having meansthereon to guide and support selected sized drill bits with theircutting lips in stationary sharpening engagement with said sharpeningsurface.
 4. A drill bit sharpener ad defined in claim 3 which includesmeans electrically insulating said motor from said sharpening head.
 5. Adrill sharpener as defined in claim 4 wherein said insulating meansincludes an insulating coupling interconnecting said shaft and a spindleto which said abrasive wheel is fixed.
 6. A drill sharpener as definedin claim 3 wherein said casing includes a pair of telescopic membersaxially trapping said motor therebetween.
 7. A drill sharpener asdefined in claim 6 which includes a baffle fixed to one of said membersand laterally supporting said motor.
 8. A drill sharpener as defined inclaim 3, wherein said casing includes separable, electrically insulatingmembers enclosing said motor, a line cord extending from said casing forconnecting said motor to an electric source, electrical switch means onsaid casing, electrical conductors within said casing and connectingsaid motor, said switch, and said line cord, said casing membersdefining a wireway confining said conductors.
 9. A drill sharpenercomprising an electric motor enclosed in a housing, said motor havingtransmission means within said housing and an output shaft accessiblefrom outside said housing, an electrically insulating casingsubstantially completely enclosing and trapping said housing therein, asharpener head fixedly supported upon said casing, an abrasive wheelrotatably supported within and upon said head and having a conical endface defining a sharpening rotatable about an axis substantially alignedwith the axis of said output shaft, means coupling said ouTput shaft andsaid abrasive wheel for conjoint rotation, said head including meanslocating drill bits with their cutting lips in stationary sharpeningengagement with said sharpening surface, electric switch means for saidmotor, said switch means being disposed within said casing and includingan electrically insulating operator accessible from outside said casing.10. A drill sharpener as defined in claim 1 wherein said coupling has acylindrical projection in said cup-shaped end adapted to fit into saidone end of said spindle, whereby to help align said spindle and saidshaft.